Transformer



June 5, 1923. 1,457,784

I E. P. MAURER TRANSFORMER v Filed Sept. 6 1919 Patented June 5, 1923.

STATES EDWARD P. MAURER,

0F CLEVELAND, OHIO.

TRANSFORMER.

Application filed September 6, 1919. Serial No. 322,069.

To all whom it may concern:

Be it known that I, EDWARD P. MAURER, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Transformers, of which the following is a full, clear, and exact description.

This invention relates to electric transformers particularly small or comparatively small transformers, such for example, as those of the bell ringing type.

The principal object of the invention is to provide a transformer with a casing of insulating material such as porcelain, composed of two arts preferably counterpart or duplicate haves adapted to be bolted together preferably through the core, the parts of the casing having oppositely disposed shoulders between which projecting portions of the core are clamped to securel support the latter and also to eliminate umming, and the corners of'each part of the casing having pockets suitably formed to accommodate the primary and secondary terminals and prevent their contacting or engaging the core or any other metallic part.

' A further object is to form the marginal and particularly the end and corner ortions of the parts of the casing, not on y so as to form the core and terminal supporting or receivin portions, but to provide reinforcements w 1ch minimize. liability of breakage which is liable .to occur if an ordinary porcelain clad transformer is dro ped any distance or otherwise receives a b ow.

Still further the invention aims to provide a construction'which eliminates the necessity of sealing the transformer proper in the casing and to so form the casin that should one part of the latter be bro en, all other arts of the transformer can be salvaged which is not true of those transformers so formed that it is necessary to fill the space around the transformer proper within the casing with a sealing compound.

Other objects are obtained by my invention which may be briefl summarized as consisting in certain nove details of construction and combinations and arran e-. ments of parts which will be described in t e specificatlon and set forth in the appended 0 same.

In the accompanying sheet of drawings wherein I have shown one embodiment of my invention which is successful in practice,

Fig. 1 is a side view of the transformer; Fig. 2 is an edge view of the same; Fig. 3 is a plan view with one-half of the casing removed showing a transformer of the core type; Fig. 4 is a similar view with the transformer removed; Fig. 5 is a transverse sectional view substantially along the line 5-5 of Fig. 1; Fig. 6 is a detail sectional view showing the preferred way of making the primary connections; and Fig. 7 is a view similar to Fig. 3 showing a transformer of the shell type, i s. 3 and 7 showing the adaptability of t e invention for transformers of both the core and shell types.

Referring. now'to the drawings, 10 represents the casing composed of two duplicate or counterpart halves 10, formed of porce-- lain or other suitable hard non-conducting material.

Each half of the casing has a base ortion 11, the base portions of the two ha ves being shaped so as to provide an air space such as shown at 12.

On its inner side each half of the casing is cupped or recessed to accommodate a transformer proper, which may be of the core type, as shown in Fig. 3, wherein 13 represents the core, whose two legs are surrounded b a primary winding 14, and aseconda win ing 15, or which may be of the shel type, as indicated in Fig. 7, wherein the middle leg of the transformer core 16 issurrounded by primary and secondary coils indicated at 17.

Along op osite sides of each half of the casing are ormed recesses. to accommodate the ends of the core, i. e. the ortions which project beyond the coils, an shoulders 18, on which the ends of the core rest. It is between these shoulders of the two halves of the casing that the ends of the. core are clamped, such as by clamping screws or bolts 19, extending through the side portions of the two halves of the casing and through the core. The depth of each recess whose base is the shoulder 18, is equal substantially to one-half the thickness of the core, so that when the"'c'ore and the two halves of the casing are secured together, the core will be so tightly clamped between the opposing shoulders of the two parts of the casing that not only'will the transformer be eilectively held in position without the necessity for any sealing compound which has been commonly employed heretofore in small trans-- former constructions, but the characteristic humming, due to vibrations of the core lamina: created by the eii ect of the A, 1, current traversing the primary, is substa tially eliminated.

At the outer sides oil the two halves of the casing the openings to accommodate the clamping screws or bolts 19 are preferably countersunk accommodate the heads of the screws and the clamping nuts which are provided thereon.

At the ends or the shoulders 18, "forming the clamping surfaces 'for the core, are provided inwardly projecting wings 20 and 21, and beyond the wings 20 are formed pool:- ets or recesses 22, to accommodate the secondary terminal members, and beyond the wings 2i. pockets or recesses 23, to accommodate the primary terminal members, From the pockets 22 there extend upwardly through the upper marginal part or": each half of the casing, halt round openings 24 to accommodate the shanks of secondary binding post screws 25 which thus project through the top of the casing at the central plane, or at the meeting faces of the two halves of the casing, and are thus also securely clamped in position by the two halves of the casing when secured together by the clamping screws or bolts 19. The heads or the binding post screws 25 lie in the pockets 22, and while they are normally clamped up against the top portion of the casing in the position shown in Fig.

3, it is obvious that the wings 20 prevent their contacting wlth the core, and thus obviate grounding or short circuiting. The

' ends of the secondary winding are soldered to the heads of these screws, or otherwise electrically connected to them.

The depth of the pockets 22 of each half of the casing is equal substantially to, or a tritle greater than one-half the width of the heads of the binding post screws 25, so that when the two halves of the casing are together, these poclrets prevent the screws turnin in the casing.

llt might be mentioned at this point that for asingle voltage transformer there will be simply two of these secondary binding posts, but for a three voltage transformer, provision will be made "for a third binding post midway between the two shown, it being possible with the same molds to form the two halves of the casing either for a single voltage or a three voltage transformer by providing openings for three binding post screws for a three voltage transformer, and blocking out the middle openings in the event that a single voltage transformer is to be produced.

From the pockets 23, half round openings 26 project laterally through the side marginal portions of each half of the casing, which openings are preferably roughened or grooved so that the primary terminal members which are preferably in the form of insulated wire 27, will be clamped between the two halves of the casing when they are secured together by the screws or bolts 19.. Preferably the pockets 23 which accommodate the primary terminals 27, are deeper than the pockets 22, the latter being just deep enough that when the two parts of the casin 1 are fitted together, these pockets will accommodate the heads of the binding post screws, whereas the pockets for the primary terminal 23 are made deeper, so that the primary terminal wires 27 can be bent back on themselves in substantially lldorm, as indicated at 27 in Fig. 6, the bends thus formed in these wires relieving the soldered joints between these wires and the ends of the primary winding from all strains created by a pull on the wires 27. By the provision of the wings 21 and the pockets which receive the bent or doubled ends of the primary wires 27, danger of short circuiting or grounding by contact between these wires. and the core is minimized.

it will be observed that when the two halves of the casing are clamped together onto the core of the transformer, and onto the primary and secondary terminal members as explained, all parts are held very securely in place with maximum protection against short circuiting or grounding. There is thus avoided entirely, the necessity of filling all open spaces within the casing with a sealing compound, and it will be noted that should one part of the easing, or both parts for that matter, be broken, the remaining part of the transformer can be salvaged since the two halves oi the casing can be readily removed from the transformer proper without injurin the latter. However, the construction is such that by the provision of the shoulders for the core, and the pockets formed in part by the wings 20 and 21, the marginal portions of the casing are considerably reinforced so that the casing is not easily broken'should it be dropped onto ahard surface from a considerable height, which would usually be sufficient to cause the breakage of a transformer casing formed in the ordinary manner.

Tn addition to the above advantageous points, the novel construction facilitates assembly, and the fact that the two halves of the casing are duplicates not only admits of a broken half being replaced readily, but obviously the cost is reduced by reason of the fact that the same molds can be used for both parts of the casing, not only for a single voltage transi'iormer, but for a three voltage transformer. Furthermore, not only can the same molds be used in forming casings adapted for one or th llli voltage transformers, but the same casings can be used for transformers designed for A. C. currents of any commercial voltage or cycles, for should there be any differences in the thickness of the transformer cores, such difference or differences could be compensated for by the use of pads between the shoulders 18 and the ends of the core, so that the same effective clamping action on the ends of the core could be obtained in any case.

Having described my invention, I claim:

'1. In combination, a transformer composed of a core and coils, and a casing composed of two parts each provided along opposite sides with recessed portions shaped to accommodate the ends of the transformer core, and having shoulders between which the ends of the core are clamped in a direction transversely of the core laminae when the two parts of the casing are secured together, the shoulders of one part of the casing engaging one side of the core, and the shoulders of the other part engaging the opposite side of the core.

' 2. In a transformer construction, a transformer core and its windings, and a casing composed of two parts, each having at the edges t ereof on opposite sides, recesses to receive theend of the core andcore engaging shoulders, the shoulders of one part engaging one side of the core and those of the other part engaging the opposite side of the core, and means passing through the two parts of the casing for securing them to gether and atthe same time clamping the core between said shoulders in a direction transversely of the laminae of the core.

3. In a transformer, a casing provided with clamping portions shaped to receive the ends of the transformer core, and having adjacent said portions pockets to accommodate transformer terminals.

4. In a transformer, a casing formed in two parts adapted to be clamped together, said parts being provided with clamping shoulders for a transformercore andbeing provided adjacent the latter with pockets to accommodate terminal members, each part being provided with inwardly projected wings separating the pockets from said shoulders.

5. A transformer comprising a core, primary and secondary windings thereon, and a casing formed in two parts between which the transformer proper is clamped, each part of the casing being shaped to accommodate a portion of the transformer proper, and having on itsinner face grooves for transformer terminal members, the latter adapted to extend out from the casing at the junction of the two parts ofthe latter.

6. A transformer comprising a core'having primary and secondary coils and an enclosing casin composed of two parts clamped toget or against the core, the two parts of the casing being recessed to accommodate the core and coils and having at their meeting faces'registering openings to accommodate terminal conductors.

7. A transformer comprising a core with primary and secondary coils and a casing composed of two duplicate parts and adapted to be clamped together against the core, the two parts of the casing having recesses to accommodate the core and coils, and recesses to accommodate the terminal members, the recesses for the terminal members extending outwardly to the exterior of the casing at the meeting faces of the two parts of the casing.

8. A transformer comprising a core with primary and secondary coils and a casing and composed of two duplicate parts adapted to be clamped together with their meeting or adjacent faces at the center plane of the transformer, each part of the casing having a recess to accommodate the core and coils with shoulders adapted to engage the ends of the core, and each part having pockets adjacent said shoulders to accommodate terminal members, and substantially half round openings extending from said pockets outwardly, the recesses, pockets and half round openings of the two parts of the casing registering when said parts are clamped together.

9. A transformer comprising a core with windings thereon, and a multi-part casing,

and bolts clamping together the parts of the casing and extending through the core.

10. A transformer comprising a core with its windings, and a two-part casing, each part of the casing having core clamping shoulders, and means for clamping together the two parts of the casing and core comprising bolts extending through the casing and through the core.

In testimony whereof, I hereunto aflix my signature.

EDWARD r. MAURER, 

